Hello, I’m making some layers for my PCB in Inkscape before bringing them into KiCad,
And from what I understand the convention is to have a small gap of around 0.05 mm as mask opening, so if there is misalignment the pads are not covered in the mask.
But I kind of want to do the reverse, as I have all exposed traces and really don’t want misalignment to result in a gap of exposed FR4 in between the trace and the mask, so thinking having a small overlap will resolve that issue…but how much is a mask going to be off…are we talking in mm?
That value which is published by the manufacturer works both ways. You have to understand it’s an x/y offset, not for shrinkage/expansion.
This means the whole layer is moved a bit in its entirety.
Ah, thank you for explaining that!
So, I could enlarge my copper or mask by that factor and both ways would alleviate the risk of the exposed board due to a misalinment.
You can widen the copper track or narrow down the mask graphics on it. See How does solder mask layer work? – the graphics describe the mask opening, so narrower graphic line exposes less copper while wider line may expose the board material, too.
Thank you, that was an externally helpful read.
As I have nothing too near to each other, I went with bumping the copper up 0.1mm so if the mask is off it should just be exposing more copper.
Maybe showing it in Kicad would be better
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